Process of treating coal and composition therefor



Patented Feb. 6, 1945 PROCESS OF TREATING COAL AND COMPOSITION THEREFORLawrence P; Crecelius, Shaker Heights, Ohio, as

Signor to The Coal Processing Company, Cleveland, Ohio, a corporation ofOhio V No Drawing. Application September 5, 1941,

Serial No. 409,659

2 Claims.

This invention relates to a process for the treating of coal and theburning of the'same, which coal contains relatively large amounts ofiron sulphur compounds, such as iron pyrites, for the purpose ofimproving the burning of the coaLobviating the efiect of deleteriousflue gases and tube slagging, and to improve the ash characteristics. I

The present invention may be properly considered in the nature of animprovement upon the invention which is set forth in my issued PatentNo. 2,089,599, granted August 10, 1937.

In that patent I described the advance in the art of power production inpower plants which was signalized by the much higher rates of burn ingof coal in furnaces than had heretofore been the practice and theaccompanying relative diminution of air supply, and I further, in thebefore mentioned patent, pointed out the fact that the change in the artof power production b the higher rates of burning of coal in furnaceshas had the effect of disqualifying and eliminatingto a very largeextent the use of coals high in iron sulphur compounds due to the factthat such coals, when subjected to the furnace conditions which had beendescribed, break down and melt the iron sulphur compounds atapproximately 2140 F., causing same to run down upon the grate surfacesof the furnace, obstructing the passage of air and fusing upon the ironof the grate parts.

In my former patent I pointed out how it was possible to utilizechlorine, present during the burning of the coal, for the purpose ofeffecting, at furnace temperatures, a decomposition of the iron sulphurcompounds and ultimately form a stable compound of both iron andsulphur, towit, ferric oxide and sulphur'dioxide.

In my prior patent the desired result was accomplished by treating thecoal with a composition comprising a suitable deliquescent halogencompound, such as calcium chloride or magnesium chloride or mixtures ofthe two, together with suitable catalytic material such as manganesedioxide, iron oxide, chromic oxide, using two or more of them together,and I specifically pointed out a composition suitable for the treatmentof coal as consisting of Percent by weight Calcium chloride 92 Potassiumdichromate 3 Manganese dioxide 3 Tannic acid 2 This composition wasdesigned to be mixed with water which was sprayed upon the coal, so

as to be distributed throughout themass of coal, either at the mine orat some time prior to the introduction of the coal into the furnacatherein to be burned. V v v a V The present invention differs from theinvention pointed out in mypatent to which reference has been made inthat adifferent composition of material is used to be applied to thecoal, for the same fundamental purposes as that described in my formerpatent, except that some additional advantages .are gained by the use ofthe new composition which will be subsequently. pointed out. 4

It may be here stated thatin connection with the present invention thecompositiomto be presently described, is mixed with water and sprayeduponthe coal, either at the mine orat any time prior to the coalbeingintroduced into the fur nace in which it is to be burned. Experience hasindicated that the quantityof the composition to be used isapproximately five per cent (5%) of the sulphur content of the coalwhich is to be burned.

Speaking in general terms, the materials used in connection with thepresent invention may be said to comprise a suitable deliquescenthalogen compound, such for instance as calcium chloride or magnesiumchloride or mixtures of the two, together with suitable catalytic.material such as chromic oxide and manganese dioxide, either one ofwhich may be used, but the catalytic effect is enhanced very materiallyby the use of both chromium oxide and manganese dioxide. In addition,dextrin is employed and potassium acid fluoride.

One suitable composition for the purpose is made up as follows:

Percent by weight Calcium chloride- 92 Chromic oxide 3 Manganese dioxide3 Dextrin 1 Potassium acid fluoride 1 Ihe chemical response inconnection with the use of calcium chloride, manganese dioxide, and

chromic oxide, when utilized in connection with the burning of coal highin compounds of iron and sulphur, is the same as that which has beendescribed in my prior Patent No. 2,089,599.

While in my prior patent the suitable composition therein mentionedincluded potassium di-v chromate, the subsequent description :r'n'ade itIn the present invention, the use of dextrln is desired because of itscolloidal property when mixed with water and therefore when the metallicoxides of manganese and chromium (in finely divided condition) are mixedwith water in which dextrin is present, the colloidal characteristic: ofthe dextrin maintains the metallic oxides in suspension in the liquidand materially assists ;in

is small because the percentage by weight of the potassium acid fluoridewhich is used is low in the composition. However, the fluorine thus lib-I erated will attack any silica or siliceous film upon I theiron sulphurparticles that may have adhered to the tube, in effect eradicating thefilm and ex- I posing the iron sulphlde to the action not only offluorine but mainly to the action of the chlosecuring a properdistribution of the before mena tioned metallic oxides when the mixtureof calcium chloride, manganese dioxide and chromic oxide is sprayed uponthe coal. Likewise, the matter of maintaining the metallic oxides, abovementioned, in suspension obviates the clogging of pipes and nozzleswhich may be a part of the apparatus used in spraying the coal.

To some extent, the dextrin functions to rea silica film forms uponthese iron sulphide par ticles (the silica coming from silica containinimpurities in the coal) which film is not readily attacked by thechlorine. But where potassium acid fluoride has been used in connectionwith the mixture with Which the coal is treated, this potassium acidfluoride, in the presence of the catalysts, which have'before beenmentioned, liberates fluorine. The quantity of fluorine liberatedManganese 'dioxide I Potassium acid, fiuoride rine, which will bedecomposed to the stable oxide of iron and sulphur dioxide.

The'present invention is applicable not only in connection with thetreatment and burning of .coaLKbut it will be understood that it is alsoapplicable to coke, lignite, peat, and other sub- ;stances of similarcategorywherein is involved the same problem of the removal of ironsulphur compounds.

Having thus described my invention, I claim; ..1.'Accomposition ofmatter for the treatment of coal comprising the following substances byweight: I

Per cent Calcium chloride Approximately 90 Approximately 3 Approximately3 Approximately" "3 '2. A composition of matter for the treatmentChromic oxide r of coal comprisingthe following substance fby 'Dextrinweight:

I Per cent Calcium chloride i Approximately 90 "Chrom-ic oxideApproximately 3 Manganese -dioxide Approximately '3 "Potassium acidfluoride Approximately 3 Approximately l LAW ENCE P. CRECELIUS.

